Technical Field
The devices and techniques described herein relate to controlling extraction of gas from landfills.
Discussion of the Related Art
Landfills typically produce landfill gas as a result of decomposition processes occurring in the waste, and methane is often a component of this landfill gas. In order to reduce emissions of methane and other contaminants in landfill gas, the landfill sites are typically capped with a layer of cover material and gas extraction systems are installed to pull landfill gas out before it can penetrate the cover layer and escape. At larger sites, these gas extraction systems can consist of a plurality of vertical and horizontal wells drilled into the landfill, which are connected with piping to one or more vacuum sources. The cover layer prevents gas from freely escaping, while the vacuum in the extraction wells pulls landfill gas into the collection system. A conventional landfill gas extraction well typically has a manual valve that adjusts the localized vacuum pressure in that well, as well as a set of ports for sampling the gas characteristics with a portable gas analyzer. Landfill gas is most often disposed of in a flare, processed for direct use, or used to power electricity generation equipment (such as generators or gas turbines).